manifest: Switch to tracker-0.16
manifest: Switch to tracker-0.16

See https://bugzilla.gnome.org/show_bug.cgi?id=696101

djdeath/gnome-ostree,GNOME/gnome-ostree,vrutkovs/vrutkovs.github.io,djdeath/gnome-ostree,chergert/gnome-continuous,vrutkovs/vrutkovs.github.io,chergert/gnome-continuous,GNOME/gnome-ostree,chergert/gnome-continuous,vrutkovs/vrutkovs.github.io,GNOME/gnome-ostree,djdeath/gnome-ostree